Interview: Just How Long Should Patients Be on Dual Antiplatelet Therapy?

May 20, 2014

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Anticipating Results from DAPT and PEGASUS In the March issue of CardioSource WorldNews, our cover story looked at the changing opinions about dual antiplatelet therapy. A variety of ongoing studies may soon provide answers to the important questions raised by clinical trials like OPTIMIZE and PARIS that were reviewed in the cover story.

At ACC.14, CSWN Executive Editor Rick McGuire spoke with Laura Mauri, MD, associate professor of medicine at Harvard Medical School and the chief science officer at the Harvard Clinical Research Institute, about two trialsDAPT and PEGASUSthat are looking at various issues and impacts of dual antiplatelet therapy.

Rick McGuire: In the case of the DAPT Study, what are the questions you're trying to answer?Laura Mauri, MD: As you probably know, there's been tremendous variation worldwide in how long patients are treated with aspirin plus a medication like clopidogrel or other thienopyridines after coronary stents are placed because we don't really know what the appropriate duration should be, in terms of preventing late stent thrombosis or other cardiovascular events. This has remained really a problematic question for cardiologists worldwide.

How many patients are being looked at in the DAPT Study, and when are data expected to be released?
We enrolled 26,000 patients worldwide. It was an incredible trial to run together with my co-principal investigator, Dean Kereiakes, MD, because sites were so enthusiastic about participating in this. We really had very broad inclusion criteria, so there are patients who are quite complex in the triallots of patients with acute coronary syndromes and diabetes. It represented a real-world population, and also a great variety of different types of approved stents.

The majority was everolimus-eluting stents, but we have a whole range of four different approved stents included in the trial, and also the different types of thienopyridines, clopidogrel and prasugrel. Patients were enrolled and then after the first year of follow-up they were randomized [to different dual antiplatelet therapy regimens] if they were still eligible. So, there was an observational period and then the randomization phase.

The primary analysis really sought to compare 1-year versus longer-term dual antiplatelet therapy after coronary stents. We expect to have the results this year; right now we're in the final phases of follow-up. Results should be here in the fall.

Great. One of the issues we address in the cover story is the fact that a lot of people are managing to stay on dual antiplatelet therapy for some time, but now the question is, "Just how long is necessary?" Hopefully we'll have some answers soon.
Right. We're really looking forward to the results; not a day goes by that I'm not asked this question. It's a question that we face both as interventional cardiologists and as general cardiologists.

Now there's another studythe PEGASUS trialthat is looking to close by the end of the year, but they probably won't present until, my guess would be early 2015. In the case of PEGASUS, can you describe what the investigators are trying to do?
Yes, they are interested in one specific drug, ticagrelor, and a population of patients who have had a myocardial infarctionnot necessarily just patients who were treated with coronary stents, but any patient with a myocardial infarction over the past year. Patients are randomized to either start ticagrelor or continue on placebo.

As you might imagine, we tend to recommend that people follow the guidelines. In terms of recommended therapy beyond the guidelines, until we know anything from PEGASUS or DAPT, do you have any recommendations?
Well, I think the guidelines stand as they are. The guidelines would recommend, after placement of drug-eluting stents, 1 year of dual antiplatelet therapy for any patient with an acute coronary syndrome. This is the recommendation even with bare-metal stents. Within the DAPT Study, we will get a chance to have a much stronger comparison of bare-metal and drug-eluting stents, as well as how long patients should be treated depending on the stent type. So, those results will be useful. I think both of these trials will be really helpful in determining whether the guidelines should change based on the results, but for now our best recommendations are to continue to follow the guidelines.

And, at 1 year, I can imagine that there are a lot of clinicians who are going, "Patients are very successfully treated on this, they have not had a problem, why not continue on it?"
Exactly, and that's the issue that we're trying to solve. There are also patients, however, that have trouble continuing because of bleeding. So, we're trying to weigh the risk and benefit between preventing hard cardiovascular endpoints and stent thrombosis versus the risk of bleeding with the longer-term therapy.